Timing control device and method for producing polyamide by continuous solid phase polycondensation reaction

Abstract

The present invention discloses a timing control device and method for producing polyamide by continuous solid-phase polycondensation reaction. The timing control device comprises a primary reactor, a secondary reactor, a first buffer tank, a second buffer tank, a first pressure transmitter, a second pressure transmitter, a first timing controller, a second timing controller and a plurality of ball valves. The timing control method performs first sequence control, second sequence control and third sequence control on the timing control device. The timing control device and method of the present invention can realize continuous solid-phase polycondensation reaction and keep the pressure of each reaction system stable. By setting different pressures for each reactor according to different reaction stages, cyclic pressure increase and pressure reduction in the intermittent polymerization reaction process can also be avoided, saving energy while protecting the reactor. In addition, the timing control device and method also have the advantages of simple operation and high degree of automation.

Description

Technical Field

[0001] The invention relates to the technical field of continuous solid phase reaction timing control, in particular to a timing control device and method for producing polyamide by continuous solid phase polycondensation reaction. Background Art

[0002] There are many types of high temperature resistant polyamide (PA for short, commonly known as nylon) prepared by solid phase polycondensation reaction, mainly PA6, PA10, PA12, PA46, PA66, etc. High temperature resistant nylon (polyamide) has the characteristics of resistance to temperatures above 150°C, good strength, low water absorption and good formability, and is widely used in the automotive and electronics industries.

[0003] In industry, intermittent polymerization is mostly used to prepare high temperature resistant nylon (polyamide). However, intermittent polymerization has many disadvantages: for example, there is a small amount of residue in the intermittent polymerization reactor, which affects the product quality; the intermittent polymerization process requires cyclic pressure increase and pressure reduction, resulting in energy waste. Therefore, how to achieve continuous solid phase polycondensation reaction of high temperature resistant nylon (polyamide) is a technical problem that needs to be solved in this field. Summary of the invention

[0004] The purpose of the present invention is to provide a timing control device and method for producing polyamide by continuous solid-phase polycondensation reaction, so as to realize continuous solid-phase polycondensation reaction and keep the pressure of each reaction system stable, avoid cyclic pressure increase and pressure reduction during intermittent polymerization reaction, save energy and protect the reactor at the same time.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A timing control device for producing polyamide by continuous solid phase polycondensation reaction, comprising: a primary reactor, a secondary reactor, a first buffer tank, a second buffer tank, a first ball valve, a second ball valve, a third ball valve, a fourth ball valve, a fifth ball valve, a sixth ball valve, a first pressure transmitter, a second pressure transmitter, a first timing controller and a second timing controller;

[0007] The outlet pipeline of the primary reactor is provided with two branches, namely a first branch and a second branch; the first branch is connected to the inlet of the first buffer tank through the first ball valve; the outlet of the first buffer tank is connected to the inlet of the secondary reactor through the fifth ball valve; the second branch is connected to the inlet of the second buffer tank through the second ball valve; the outlet of the second buffer tank is connected to the inlet of the secondary reactor through the sixth ball valve;

[0008] The first gas boost port of the first buffer tank is connected to the external gas pipeline through the third ball valve; the second gas boost port of the second buffer tank is connected to the external gas pipeline through the fourth ball valve;

[0009] The first timing controller is connected to the first ball valve, the third ball valve and the fifth ball valve respectively; the first timing controller is also connected to the first buffer tank through the first pressure transmitter; the second timing controller is connected to the second ball valve, the fourth ball valve and the sixth ball valve respectively; the second timing controller is also connected to the second buffer tank through the second pressure transmitter.

[0010] Optionally, the first ball valve, the first pressure transmitter, the third ball valve, the fifth ball valve and the first timing controller constitute a first timing control system; the second ball valve, the second pressure transmitter, the fourth ball valve, the sixth ball valve and the second timing controller constitute a second timing control system.

[0011] Optionally, the ball valve is a pneumatic ball valve or an electric ball valve.

[0012] Optionally, the gas is nitrogen, argon or carbon dioxide.

[0013] Optionally, the timing control device further includes: a pressure stabilizing valve; the third ball valve and the fourth ball valve are respectively connected to the external gas pipeline through the pressure stabilizing valve.

[0014] Optionally, the pressure of the primary reactor is different from that of the secondary reactor.

[0015] The present invention also provides a timing control method for producing polyamide by continuous solid phase polycondensation reaction, the timing control method is applied to the timing control device, and the timing control method comprises:

[0016] The first timing controller realizes a first sequential control by controlling the first ball valve, the third ball valve, the fifth ball valve and the first pressure transmitter;

[0017] The first timing controller realizes the second sequential control by controlling the first ball valve, and the second timing controller realizes the second sequential control by controlling the second ball valve, the fourth ball valve, the sixth ball valve and the second pressure transmitter;

[0018] The second timing controller realizes a third sequential control by controlling the second ball valve, and the first timing controller realizes a third sequential control by controlling the first ball valve, the third ball valve, the fifth ball valve and the first pressure transmitter;

[0019] The second sequence control and the third sequence control are cycled in sequence until the production process is completed.

[0020] Optionally, the first timing controller implements a first sequential control by controlling the first ball valve, the third ball valve, the fifth ball valve and the first pressure transmitter, specifically including:

[0021] The first timing controller opens the third ball valve, controls the pressure of the first pressure transmitter to reach a set pressure value within a preset time, and interlocks to close the third ball valve, while opening the first ball valve; after the set time, closes the first ball valve and opens the fifth ball valve; after the set time, closes the fifth ball valve.

[0022] Optionally, the first timing controller controls the first ball valve, and the second timing controller controls the second ball valve, the fourth ball valve, the sixth ball valve and the second pressure transmitter to implement the second sequential control, which specifically includes:

[0023] The first timing controller controls the first ball valve to start unloading, and at the same time the second timing controller opens the fourth ball valve, controls the pressure of the second pressure transmitter to reach a set pressure value within a preset time, and interlocks to close the fourth ball valve; while closing the first ball valve, the second ball valve is opened, and after the set time, the second ball valve is closed, and the sixth ball valve is opened, and after the set time, the sixth ball valve is closed.

[0024] Optionally, the second timing controller controls the second ball valve, and the first timing controller controls the first ball valve, the third ball valve, the fifth ball valve and the first pressure transmitter to implement a third sequential control, specifically including:

[0025] The second timing controller controls the second ball valve to start unloading, and at the same time the first timing controller opens the third ball valve, controls the pressure of the first pressure transmitter to reach a set pressure value within a preset time, and interlocks to close the third ball valve; while closing the second ball valve, the first ball valve is opened, and after the set time, the first ball valve is closed, and the fifth ball valve is opened, and after the set time, the fifth ball valve is closed.

[0026] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0027] The present invention provides a timing control device and a timing control method for producing polyamide by continuous solid phase polycondensation reaction. The timing control device includes: a primary reactor, a secondary reactor, a first buffer tank, a second buffer tank, a first ball valve, a second ball valve, a third ball valve, a fourth ball valve, a fifth ball valve, a sixth ball valve, a first pressure transmitter, a second pressure transmitter, a first timing controller and a second timing controller; the outlet pipeline of the primary reactor is provided with two branches, namely a first branch and a second branch; the first branch is connected to the inlet of the first buffer tank through the first ball valve; the outlet of the first buffer tank is connected to the inlet of the secondary reactor through the fifth ball valve; the second branch is connected to the inlet of the second buffer tank through the second ball valve; the outlet of the second buffer tank is connected to the inlet of the second buffer tank through the second ball valve; the outlet of the second buffer tank is connected to the inlet of the second buffer tank through the fifth ... The first gas boost port of the first buffer tank is connected to the inlet of the secondary reactor through the sixth ball valve; the first gas boost port of the first buffer tank is connected to the external gas pipeline through the third ball valve; the second gas boost port of the second buffer tank is connected to the external gas pipeline through the fourth ball valve; the first timing controller is respectively connected to the first ball valve, the third ball valve and the fifth ball valve; the first timing controller is also connected to the first buffer tank through the first pressure transmitter; the second timing controller is respectively connected to the second ball valve, the fourth ball valve and the sixth ball valve; the second timing controller is also connected to the second buffer tank through the second pressure transmitter. The timing control method is applied to the timing control device, and the timing control method includes: the first timing controller realizes the first sequence control by controlling the first ball valve, the third ball valve, the fifth ball valve and the first pressure transmitter. The first timing controller realizes the second sequence control by controlling the first ball valve, and the second timing controller realizes the second sequence control by controlling the second ball valve, the fourth ball valve, the sixth ball valve and the second pressure transmitter. The second timing controller controls the second ball valve, and the first timing controller controls the first ball valve, the third ball valve, the fifth ball valve and the first pressure transmitter to achieve the third sequential control. The second sequential control and the third sequential control are cycled in sequence. The timing control device and method of the present invention can realize continuous solid phase polycondensation reaction and keep the pressure of each reaction system stable. Different pressures are set for each reactor according to different reaction stages, avoiding cyclic pressure increase and pressure reduction during intermittent polymerization reaction, saving energy and protecting the reactor.

[0028] In addition, the timing control device and method also have the advantages of simple operation and high degree of automation, and can be widely promoted and applied to the continuous polymerization reaction of materials such as nylon, polypropylene, and polyethylene, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0030] Figure 1 A schematic diagram of the structure of a timing control device for producing polyamide by continuous solid phase polycondensation reaction provided by the present invention;

[0031] Explanation of symbols: 1. Primary reactor, 2. Secondary reactor, 3. First buffer tank, 4. Second buffer tank, 501. First ball valve, 502. Second ball valve, 503. Third ball valve, 504. Fourth ball valve, 505. Fifth ball valve, 506. Sixth ball valve, 6. First pressure transmitter, 7. Second pressure transmitter, 8. First timing controller, 9. Second timing controller, 10. Pressure regulating valve. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] The purpose of the present invention is to provide a timing control device and method for producing polyamide by continuous solid-phase polycondensation reaction, so as to realize continuous solid-phase polycondensation reaction and keep the pressure of each reaction system stable, avoid cyclic pressure increase and pressure reduction during intermittent polymerization reaction, save energy and protect the reactor at the same time.

[0034] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0035] Figure 1 The present invention provides a schematic diagram of the structure of a timing control device for producing polyamide by continuous solid phase polycondensation reaction. Figure 1 As shown, the present invention is a timing control device for producing polyamide by continuous solid phase polycondensation reaction, comprising: a primary reactor 1, a secondary reactor 2, a first buffer tank 3, a second buffer tank 4, a first ball valve 501, a second ball valve 502, a third ball valve 503, a fourth ball valve 504, a fifth ball valve 505, a sixth ball valve 506, a first pressure transmitter 6, a second pressure transmitter 7, a first timing controller 8 and a second timing controller 9.

[0036] Specifically, the outlet pipeline of the primary reactor 1 is provided with two branches, namely, a first branch and a second branch. The first branch is connected to the inlet of the first buffer tank 3 through the first ball valve 501, and the outlet of the first buffer tank 3 is connected to the inlet of the secondary reactor 2 through the fifth ball valve 505. The second branch is connected to the inlet of the second buffer tank 4 through the second ball valve 502, and the outlet of the second buffer tank 4 is connected to the inlet of the secondary reactor 2 through the sixth ball valve 506. That is, the outlet pipeline of the primary reactor 1 is provided with two branches, one branch is connected to the first ball valve 501 and the first buffer tank 3, and the other branch is connected to the second ball valve 502 and the second buffer tank 4. Further, the outlet of the first buffer tank 3 is connected to the fifth ball valve 505, and the outlet of the second buffer tank 4 is connected to the sixth ball valve 506, and then connected to the inlet of the secondary reactor 2 through the pipeline.

[0037] The first buffer tank 3 is provided with a first gas boost port, which is connected to the external gas pipeline through the third ball valve 503 and the pressure-stabilizing valve 10. The second buffer tank 4 is provided with a second gas boost port, which is connected to the external gas pipeline through the fourth ball valve 504 and the pressure-stabilizing valve 10. In practical applications, the gas may be nitrogen, argon or carbon dioxide.

[0038] As a specific embodiment, a nitrogen boost port may be provided at the top of the first buffer tank 3, and connected to the third ball valve 503. A nitrogen boost port is also provided at the top of the second buffer tank 4, and connected to the fourth ball valve 504, and the two pipelines are connected to the pressure regulating valve 10 and the external nitrogen pipeline through a pipeline. In practical applications, the pressure of the primary reactor 1 is different from that of the secondary reactor 2, and the corresponding pressure is set according to different stages of the solid phase polycondensation reaction.

[0039] The present invention also constitutes two timing control systems. Specifically, the first timing control system includes the first ball valve 501, the first pressure transmitter 6, the third ball valve 503, the fifth ball valve 505 and the first timing controller 8. The first timing controller 8 is connected to the first ball valve 501, the third ball valve 503 and the fifth ball valve 505 respectively; the first timing controller 8 is also connected to the first buffer tank 3 through the first pressure transmitter 6.

[0040] The second timing control system includes the second ball valve 502, the second pressure transmitter 7, the fourth ball valve 504, the sixth ball valve 506 and the second timing controller 9. The second timing controller 9 is connected to the second ball valve 502, the fourth ball valve 504 and the sixth ball valve 506 respectively; the second timing controller 9 is also connected to the second buffer tank 4 through the second pressure transmitter 7. The two timing control systems are set to be associated, that is, the two timing control systems are operated in sequence, and one timing control system is always kept running, forming a material unloading control system.

[0041] In practical applications, all ball valves can be pneumatic ball valves or electric ball valves.

[0042] In practical applications, the first timing controller 8 and the second timing controller 9 are programmable logic controllers PLC, such as Siemens' S7-1500, S7-300, etc.

[0043] In practical applications, depending on different products, the reactors can be connected in series in 2-5 stages, that is, a connection relationship and control method similar to that of the first-stage reactor 1 and the second-stage reactor 2 are adopted. The second-stage reactor 2 can also be connected in series with a third-stage reactor, a fourth-stage reactor and a fifth-stage reactor in sequence.

[0044] The present invention provides a timing control device for producing polyamide by continuous solid phase polycondensation reaction, which can operate continuously, realize continuous solid phase polycondensation reaction and keep the pressure of each reaction system stable. In addition, different pressures are set for each reactor according to different reaction stages, which can avoid cyclic pressure increase and pressure reduction during intermittent polymerization reaction, save energy and protect the reactor. In addition, the timing control device also has the advantages of simple operation and high degree of automation.

[0045] The present invention also provides a timing control method for producing polyamide by continuous solid phase polycondensation reaction, the timing control method is applied to the timing control device, and the timing control method comprises:

[0046] First sequence control: The first timing controller 8 realizes the first sequence control by controlling the first ball valve 501, the third ball valve 503, the fifth ball valve 505 and the first pressure transmitter 6. Specifically, the first timing controller 8 opens the third ball valve 503, controls the pressure of the first pressure transmitter 6 to reach the set pressure value within the preset time, closes the third ball valve 503 in a chain manner, and opens the first ball valve 501 at the same time; after the set time, closes the first ball valve 501 and opens the fifth ball valve 505; after the set time, closes the fifth ball valve 505. In actual applications, the set value can be modified as needed.

[0047] Second sequential control: The first timing controller 8 realizes the second sequential control by controlling the first ball valve 501, and the second timing controller 9 realizes the second sequential control by controlling the second ball valve 502, the fourth ball valve 504, the sixth ball valve 506 and the second pressure transmitter 9. Specifically, the first timing controller 8 controls the first ball valve 501 to start unloading, and the second timing controller 9 opens the fourth ball valve 504, controls the pressure of the second pressure transmitter 7 to reach the set pressure value within the preset time, and closes the fourth ball valve 504 in a chain manner; closes the first ball valve 501 and opens the second ball valve 502 at the same time, after the set time, closes the second ball valve 502, opens the sixth ball valve 506, and after the set time, closes the sixth ball valve 506.

[0048] Third sequential control: The second timing controller 9 realizes the third sequential control by controlling the second ball valve 502, and the first timing controller 8 realizes the third sequential control by controlling the first ball valve 501, the third ball valve 503, the fifth ball valve 505 and the first pressure transmitter 6. Specifically, the second timing controller 9 controls the second ball valve 502 to start unloading, and at the same time, the first timing controller 8 opens the third ball valve 503, controls the pressure of the first pressure transmitter 6 to reach the set pressure value within the preset time, and closes the third ball valve 503 in a chain manner; closes the second ball valve 502 and opens the first ball valve 501 at the same time, after the set time, closes the first ball valve 501, opens the fifth ball valve 505, and after the set time, closes the fifth ball valve 505.

[0049] The second sequence control and the third sequence control are cycled in sequence until the production process is completed.

[0050] Two specific embodiments of the timing control method of the present invention are provided below.

[0051] Embodiment 1:

[0052] like Figure 1 As shown, the volume of the first buffer tank 3 and the second buffer tank 4 is set to 0.1m 3 The reaction pressure of the primary reactor 1 is 2.0 MPa, and the reaction pressure of the secondary reactor 2 is 0.5 MPa.

[0053] First sequence control: the first timing controller 8 opens the third ball valve 503, controls the pressure of the first pressure transmitter 6 to reach 1.6MPa within 3S, closes the third ball valve 503 in a chain manner, and opens the first ball valve 501 at the same time; after 15S, closes the first ball valve 501 and opens the fifth ball valve 505; after 15S, closes the fifth ball valve 505.

[0054] Second sequential control: the first timing controller 8 controls the first ball valve 501 to start unloading, and at the same time the second timing controller 9 opens the fourth ball valve 504, controls the pressure of the second pressure transmitter 7 to reach 1.6MPa within 3S, and interlocks to close the fourth ball valve 504; closes the first ball valve 501 and opens the second ball valve 502 at the same time, and after 15S, closes the second ball valve 502, opens the sixth ball valve 506, and after 15S, closes the sixth ball valve 506.

[0055] The third sequential control: the second timing controller 9 controls the second ball valve 502 to start unloading, and at the same time the first timing controller 8 opens the third ball valve 503, controls the pressure of the first pressure transmitter 6 to reach 1.6MPa within 3S, and interlocks to close the third ball valve 503; while closing the second ball valve 502, open the first ball valve 501, after 15S, close the first ball valve 501, open the fifth ball valve 505, and after 15S, close the fifth ball valve 505.

[0056] The second sequence control and the third sequence control are cycled in sequence until the polyamide production process is completed. The first sequence setting value can be modified as needed.

[0057] Embodiment 2:

[0058] like Figure 1 As shown, the volume of the first buffer tank 3 and the second buffer tank 4 is set to 0.1m 3 The reaction pressure of the primary reactor 1 is 2.6 MPa, and the reaction pressure of the secondary reactor 2 is 0.5 MPa.

[0059] First sequence control: the first timing controller 8 opens the third ball valve 503, controls the pressure of the first pressure transmitter 6 to reach 2.2MPa within 5S, closes the third ball valve 503 in a chain manner, and opens the first ball valve 501 at the same time; after 15S, closes the first ball valve 501 and opens the fifth ball valve 505; after 15S, closes the fifth ball valve 505.

[0060] Second sequential control: the first timing controller 8 controls the first ball valve 501 to start unloading, and at the same time the second timing controller 9 opens the fourth ball valve 504, controls the pressure of the second pressure transmitter 7 to reach 2.2MPa within 5S, and interlocks to close the fourth ball valve 504; closes the first ball valve 501 and opens the second ball valve 502 at the same time, and after 15S, closes the second ball valve 502, and at the same time opens the sixth ball valve 506, and after 15S, closes the sixth ball valve 506.

[0061] The third sequential control: the second timing controller 9 controls the second ball valve 502 to start unloading, and at the same time the first timing controller 8 opens the third ball valve 503, controls the pressure of the first pressure transmitter 6 to reach 2.2MPa within 5S, and interlocks to close the third ball valve 503; while closing the second ball valve 502, open the first ball valve 501, and after 15S, close the first ball valve 501, and at the same time open the fifth ball valve 505, and after 15S, close the fifth ball valve 505.

[0062] The second sequence control and the third sequence control are cycled in sequence until the polyamide production process is completed. The first sequence setting value can be modified as needed.

[0063] The present invention provides a timing control device and method for producing polyamide by continuous solid phase polycondensation reaction, which can realize continuous solid phase polycondensation reaction, and the pressure of each reaction system remains stable. In addition, the timing control device and method also have the advantages of simple operation and high degree of automation. Obviously, the timing control device and method of the present invention can also be widely promoted and applied to the continuous polymerization reaction of materials such as nylon, polypropylene, polyethylene, etc., and has broad application prospects.

[0064] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0065] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A timing control device for producing polyamide by continuous solid phase polycondensation reaction, characterized in that: include: A primary reactor, a secondary reactor, a first buffer tank, a second buffer tank, a first ball valve, a second ball valve, a third ball valve, a fourth ball valve, a fifth ball valve, a sixth ball valve, a first pressure transmitter, a second pressure transmitter, a first timing controller, and a second timing controller; The outlet pipeline of the primary reactor is provided with two branches, namely a first branch and a second branch; the first branch is connected to the inlet of the first buffer tank through the first ball valve; the outlet of the first buffer tank is connected to the inlet of the secondary reactor through the fifth ball valve; the second branch is connected to the inlet of the second buffer tank through the second ball valve; the outlet of the second buffer tank is connected to the inlet of the secondary reactor through the sixth ball valve; The first gas boost port of the first buffer tank is connected to the external gas pipeline through the third ball valve; the second gas boost port of the second buffer tank is connected to the external gas pipeline through the fourth ball valve; The first timing controller is connected to the first ball valve, the third ball valve and the fifth ball valve respectively; the first timing controller is also connected to the first buffer tank through the first pressure transmitter; the second timing controller is connected to the second ball valve, the fourth ball valve and the sixth ball valve respectively; the second timing controller is also connected to the second buffer tank through the second pressure transmitter; The first ball valve, the first pressure transmitter, the third ball valve, the fifth ball valve and the first timing controller constitute a first timing control system; the second ball valve, the second pressure transmitter, the fourth ball valve, the sixth ball valve and the second timing controller constitute a second timing control system; The ball valve is a pneumatic ball valve or an electric ball valve.

2. The timing control device according to claim 1, characterized in that: The gas is nitrogen, argon or carbon dioxide.

3. The timing control device according to claim 1, characterized in that: The timing control device further includes: a pressure stabilizing valve; the third ball valve and the fourth ball valve are respectively connected to the external gas pipeline through the pressure stabilizing valve.

4. The timing control device according to claim 1, characterized in that: The pressure of the primary reactor is different from that of the secondary reactor.

5. A timing control method for producing polyamide by continuous solid phase polycondensation reaction, characterized in that: The timing control method is applied to the timing control device according to claim 1, and the timing control method comprises: The first timing controller realizes a first sequential control by controlling the first ball valve, the third ball valve, the fifth ball valve and the first pressure transmitter; The first timing controller realizes the second sequential control by controlling the first ball valve, and the second timing controller realizes the second sequential control by controlling the second ball valve, the fourth ball valve, the sixth ball valve and the second pressure transmitter; The second timing controller realizes a third sequential control by controlling the second ball valve, and the first timing controller realizes a third sequential control by controlling the first ball valve, the third ball valve, the fifth ball valve and the first pressure transmitter; The second sequence control and the third sequence control are cycled in sequence until the production process is completed.

6. The timing control method according to claim 5, characterized in that: The first timing controller realizes a first sequential control by controlling the first ball valve, the third ball valve, the fifth ball valve and the first pressure transmitter, specifically including: The first timing controller opens the third ball valve, controls the pressure of the first pressure transmitter to reach a set pressure value within a preset time, and interlocks to close the third ball valve, while opening the first ball valve; after the set time, closes the first ball valve and opens the fifth ball valve; after the set time, closes the fifth ball valve.

7. The timing control method according to claim 6, characterized in that: The first timing controller controls the first ball valve, and the second timing controller controls the second ball valve, the fourth ball valve, the sixth ball valve and the second pressure transmitter to implement the second sequential control, which specifically includes: The first timing controller controls the first ball valve to start unloading, and at the same time the second timing controller opens the fourth ball valve, controls the pressure of the second pressure transmitter to reach a set pressure value within a preset time, and interlocks to close the fourth ball valve; while closing the first ball valve, the second ball valve is opened, and after the set time, the second ball valve is closed, and the sixth ball valve is opened, and after the set time, the sixth ball valve is closed.

8. The timing control method according to claim 7, characterized in that: The second timing controller controls the second ball valve, and the first timing controller controls the first ball valve, the third ball valve, the fifth ball valve and the first pressure transmitter to implement the third sequential control, which specifically includes: The second timing controller controls the second ball valve to start unloading, and at the same time the first timing controller opens the third ball valve, controls the pressure of the first pressure transmitter to reach a set pressure value within a preset time, and interlocks to close the third ball valve; while closing the second ball valve, the first ball valve is opened, and after the set time, the first ball valve is closed, and the fifth ball valve is opened, and after the set time, the fifth ball valve is closed.

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